Many food processors based essentially on a type of food processor described in the specification of British patent No. 1,380,318 have been marketed throughout the world.
Such food processors referred to as "the kind described" consist of a base containing an electric driving motor and electric switch means for controlling the operation of the driving motor, an aperture in the upper surface of the base through which a driving shaft from the said motor projects, a substantially cylindrical food processing container, complementary means on the container whereby the container is removably attached to the upper surface of the base with the driving motor shaft projecting through a hole in the bottom of the container, a sleeve in the container surrounding said hole and projecting upwardly into the container to form an annular liquid containing well around the hole, externally accessible means on the base associated with the electric switch means, a lid adapted to be removably attached about the periphery of the container, means on the container arranged to co-operate with said externally accessible means and means on the lid co-operating with said last mentioned means in such a manner that, when the lid is fixed to the container in a predetermined relationship, the said electric switch means is actuated.
The means on the container arranged to co-operate with the said externally accessible means usually consist of a shaft or like longitudinally extending member arranged at one side of the container and extending parallel to the axis thereof and movable axially against the action of a metallic spring acting to urge it in a direction away from the base. When the lid is correctly positioned an extension of the lower end of the member makes contact with said externally accessible means on the base actuating the switch means.
It has now been appreciated that containers for food processors of the kind described above can also be used as containers for cooking food processed in the food processor in a microwave oven thus avoiding the necessity for transferring the processed food to another container. With existing containers however this is not practical because of the presence of the metallic spring; as is well known, metals placed in a microwave oven are heated to high temperatures. Furthermore such longitudinally extending members are usually made of nylon which, if subjected to heat, tend to buckle. An object of the present invention is to provide a container for such a food processor which can be placed in a microwave oven with food in it and the food cooked in that container.
It has been further realised that one use of such a container would be for the baking of cakes. The volume of food to be processed that can be placed in the container is, however, limited by the height of the sleeve. If however, a cake mixture is created in the food processor with the level of the mixture slightly below the top of the sleeve and such a mixture is then baked in a microwave oven the cake mixture will rise and expand to fill the entire volume of the container. It is thus a further object of the invention to provide a form of lid which will permit this expansion to take place without overflow down the sleeve.